1. Field of the Invention
The present invention relates to a vehicle that includes a vehicle body frame that can lean and two front wheels.
2. Description of the Related Art
A known vehicle includes a vehicle body frame that leans to the left or right when the vehicle is cornering and two front wheels that are aligned in a left-and-right direction of the vehicle body frame (for example, refer to Japanese Patent Unexamined Publication JP-A-2005-313876, U.S. Design patent D547,242S and Catalogo partidi ricambio, MP3 300 LT Mod. ZAPM64102, Piaggio).
The vehicle including the vehicle body frame that can lean and two front wheels, also includes a link mechanism. The link mechanism includes an upper cross portion and a lower cross portion. In addition, the link mechanism also includes a right side portion which supports right end portions of the upper cross portion and the lower cross and a left side portion which supports left end portions of the upper cross portion and the lower cross portion. Middle portions of the upper cross portion and the lower cross portion are supported on the vehicle body frame directly forward of a steering shaft. The upper cross portion and the lower cross portion are supported on the vehicle body frame so as to turn about axes that extend substantially in a front-and-rear direction of the vehicle body frame. The upper cross portion and the lower cross portion turn relative to the vehicle body frame as the vehicle body frame leans, such that a relative position of the two front wheels in an up-and-down direction of the vehicle body frame changes. The upper cross portion and the lower cross portion are provided above the two front wheels in the up-and-down direction of the vehicle body frame when the vehicle body frame rests in an upright state.
The vehicle including the vehicle body frame that can lean and two front wheels includes a right shock absorbing device which supports the right front wheel so as to move in the up-and-down direction of the vehicle body frame and a left shock absorbing device which supports the left front wheel so as to move in the up-and-down direction of the vehicle body frame. The right shock absorbing device is supported on the right side portion so as to turn about an axis of the right side portion. The left shock absorbing device is supported on the left side portion so as to turn about an axis of the left side portion. The vehicles described in Japanese Patent Unexamined Publication JP-A-2005-313876 and U.S. Design patent D547,242S include a handlebar, a steering shaft, and a turning transmission mechanism. The handlebar is fixed to the steering shaft. The steering shaft is supported on the vehicle body frame so as to turn relative thereto. When the handlebar is turned, the steering shaft also turns. The turning transmission mechanism transfers the turning motion of the steering shaft to the right shock absorbing device and the left shock absorbing device.
The vehicle including the vehicle body frame that can lean and two front wheels includes many on-board components provided on the periphery of the steering shaft. The on-board components include lamps such as a headlamp, a radiator, a reservoir tank, electric components such as a horn, and a main switch of the vehicle, a storage box, a storage pocket and the like.
In the vehicles described in Japanese Patent Unexamined Publication JP-A-2005-313876 and U.S. Design patent D547,242S, loads received by the right front wheel and the left front wheel are transferred to the link mechanism by way of the right shock absorbing device or the left shock absorbing device. The loads are transferred to the right side portion or the left side portion from the right shock absorbing device or the left shock absorbing device. The loads are transferred to the upper cross portion and the lower cross portion from the right side portion or the left side portion. The loads are transferred further to the vehicle body frame that is positioned on the periphery of the steering shaft from the upper cross portion and the lower cross portion. The link mechanism includes bearings provided between the right side portion or the left side portion and the upper cross portion and the lower cross portion and bearings provided between the upper cross portion and the lower cross portion and the vehicle body frame. These bearings enable the right side portion or the left side portion to turn smoothly relative to the upper cross portion and the lower cross portion and the upper cross portion and the lower cross portion to turn smoothly relative to the vehicle body frame. The bearings also transfer the loads received by the link mechanism to the vehicle body frame. Additionally, the right side portion, the left side portion, the upper cross portion, and the lower cross portion are each highly rigid members in order to enhance the function of turning smoothly and the function of transferring the loads. This enlarges the external size of the right side portion, the left side portion, the upper cross portion, and the lower cross portion. This results in enlargement of the link mechanism including those portions. Further, enlargement of the link mechanism results in a further expansion of the movable range of the link mechanism.
The vehicles described in Japanese Patent Unexamined Publication JP-A-2005-313876 and U.S. Design patent D547,242S include the link mechanism provided on the periphery of the steering shaft so as to move as the vehicle body frame leans. Because of this, in the vehicle including the vehicle body frame that can lean and two front wheels, it is required that interference of the movable range of the link mechanism with the on-board components is avoided. This requires enhancing the degree of freedom when designing the link mechanism in the vehicle that includes the vehicle body frame that can lean and the two front wheels.